Formation of a protein-tannin complex to remove astringency during processing of Western-style persimmon jelly

摘要

The astringency of persimmon fruits is often removed by treating the fruits with carbon dioxide, dry ice, alcohol, or other agents before shipping the fruit to market or processing food containing a paste made from astringent varieties of persimmon. We have established a new and versatile method to remove astringency by mixing an astringent persimmon paste with protein-rich foods in processing a confectionery with persimmon paste. This method was applied to process Western-style jelly containing astringent persimmon paste. To examine the efficacy of removing soluble persimmon tannin using proteins, soy milk was used as the protein source to make Western-style jelly using a gelling agent, sugar, and astringent persimmon paste, with astringent persimmon paste treated with carbon dioxide before processing as a control. The soy milk effectively removed the astringency of jelly made from astringent persimmon. Moreover, the taste, quality, and physical properties of jelly made with astringent persimmon paste were better than those made from persimmon paste from which the astringency was removed before processing. Jelly from astringent paste exhibited more elasticity, less syneresis (liquid separation from the gel) and smoother texture. Jelly made from the non-astringent paste collapsed after removal from the cup. These results suggest that protein in soy milk not only effectively removes the astringency of food products made from astringent persimmon paste, but also that it is a suitable ingredient formanufacturing high-quality, Western-style confectionery from astringent persimmon fruits without removing astringency in advance.